Disc for upgrading work of explosives



Dec. 3, 1963 c. E. GREBE 3,112,701

DISC FOR UPGRADING WORK OF EXPLOSIVES Filed Aug. 11, 1960 lillllll IN V EN TOR. Car/6'. Grebe United States Patent 3,112,701 DISC FGR UPGRADHNG WORK OF EXPLOSTVE Carl E. Grebe, Midland, Mich, assiguor to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Filed Aug. 11, 1969, Ser. No. 483% 3 Claims. or. 1e2 22 This invention is related to explosives and more par.- ticularly is concerned with a device for upgrading and directionalizing the effective Work realized from an explosive blast.

it is a principal object of the present invention to provide a device for improving the amount of useful work that can be obtained from a given amount of explosive. It is a further object of the present invention to provide a device which promotes the directionalization of the energy released in an explosive blast both downward and outward from the source of the explosion site.

It is another object of the present invention to provide a device which in addition to upgrading the work which can be obtained from a given explosive also provides a means of positioning an explosive detonator, such as a shaped charge, in a bore hole.

Additionally, it is an object of the present invention to provide a device for use with an explosive in a bore hole whereby increased rock breakage per unit of explosive is realized over that normally obtained.

Still another object of the present invention is to provide a device for upgrading the work obtainable from ordinarily low sensitivity bulk explosives which permits ready admission of such explosives into bore holes around and in contact with said device.

Other objects and advantages will become apparent from the detailed description presented hereinafter and by reference to the accompanying drawings.

The device of the instant invention useful in effecting the upgrading of explosive work of a given explosive in cylindrical form is a substantially circular member, preferably having a slight curvature so as to be essentially saucer-shaped and defining openings within the wall of said member.

FIGURE 1 presents a lateral view of one embodiment of a circular disc, partially cutaway.

FIGURE 2 shows a top view of the disc of FIGURE 1.

FIGURE 3 shows an explosive device which comprises in combination a cylindrical explosive and saucer shaped discs confined in a bore hole.

The circular substantially saucer-shaped disc 11 has a thick outer rim 12. having a notch 13 on its top side 14 and a second notch 15 on the bottom side 16. These notches are so designed that they permit self-stacking of discs 11 one on top of another by fitting notch 15 on the bottom of one disc into notch 13 on the top of another disc. A sloping saucer-shaped wall or extension 17 leads inwardly from the inside wall 18 of the rim 12 and connects this rim 12 with the rim 19 of a central circular reinforcing member 2%) in the shape of a bottom of a. saucer and defining a center opening 2.1. The extension 17 further defines a series of openings 22; spaced at equal intervals around the saucer shaped wall 17. Each opening 22 extends in length over almost the entire section of the wall 17 between the rim .12 and the reinforcing member 20 and is defined in width by the extent of a twenty degree angle extending outward [from the center axis of the opening 21.

The circular center opening 21 is designed to accommodate an explosive detonator, such as a shaped charge. Advantageously, this opening will hold the shaped charge so that its principal axis of detonation is normal to the plane of the diameter of this opening.

The discs can be made from a variety of conducting and nonconducting materials but preferably will be fabricated from a light metal such as magnesium, aluminum, magnesium alloy or an aluminum alloy.

The devices are fabricated by any of a. variety of means; e.g., sand casting, stamping, deep drawing, permanent mold casting, die casting, forging, etc. For example, a particularly useful and commercially acceptable disc is prepared by die casting utilizing, for example, ASI M designated AZ91B magnesium alloy (nominal composition 9 percent aluminum, 0.15 percent manganese, 0.7 percent zinc, balance magnesium) or the ASIM designated SO84 aluminum alloy (nominal composition 8-9 percent silicon, 3.5 percent copper, balance aluminum).

In the preparation of such light metal die cast discs, because of the nature of their intended use, these can tolerate (1) wide variations in alloy composition, (2) broad dimensional die casting tolerances, (3) porosity and (4) minor impurity inclusion, laps and cold shuts in the casting. Additionally, the cast discs will be given only a rough trim flash grinding with no finish grinding or other finish treatment being required.

The discs themselves are prepared having an outside diameter from about 3 inches to about 16 inches, but for most commercial blasting the discs will be from about 6 to about '12 inches in outside diameter so as to be accommodated by the corresponding diametered b o-re holes.

The thickness of the outer rim 12 and rim 1-9 of the inner circular member 2% are such so as to give dimensional stability to the disc while the extension 17 joining these can be of a minimum wall thickness as is consistent with non-premium casting costs.

The eiiectiveness and utility of the discs when placed in an explosive load is demonstrated by the following example.

A comparative set of tests was run in a series of 9 inch diameter commercial bore holes drilled in taco-nite. One set of holes was loaded to a depth of about 30 feet with coarse metal chips (50-50 magnesium and aluminum) and had perforated saucer-like discs placed laterally at about 3 foot intervals up through the bore hole. A shaped charge initiator, armed with P-rimacord, was placed in the center opening of the top disc before this was lowered into the bore hole. A liquid ammoniacal solution of ammonium nitrate (containing on a weight basis 4-9 percent water, 25-3 0 percent ammonia, balance ammonium nitrate) was poured into the bore hole. This solution percolated through the metal, passing through the openings of the discs and filled the bore hole to the lateral movement outward from the bench face of readily shovelable rock was produced.

A second series of bore holes, utilizing the same explosive composition as above, but eliminating the perforated,

saucer-like discs from the charge, was loaded, armed stemmed and fired. Detonation of the loads in these holes gave good rock breakage, but resulted in essentially no lateral throw and produced some material which required secondary blasting.

Various modifications can be made in the device of the present invention without departing from the spirit or scope thereof for it is understood that 1 limit myself only as defined in the appended claims.

I claim:

1. An explosive device providing upgraded explosive 3,112,701 Patented Dec. 3., 1963 work which comprises in combination a cylindrical explosive having positioned therein at intervals laterally along the length of said explosive electron conducting substantially saucer-shaped discs and a confining structure for said explosive and discs, said discs having a thick continuous outer rim, said rim having a notch on the top and a notch on the bottom, said notch on the top of said rim of said saucer-shaped disc fitting said notch on the bottom of another of said saucer-shaped discs whereby said discs can be self-stacked, a thin wall extending inwardly from said continuous outer rim to the rim of a central circular reinforcing member, said thin Wall defining a series of openings spaced at equal intervals around said wall and extending in length over almost the entire section of the thin wall between said continuous outer rim and the rim of said central circular reinforcing member and said circular reinforcing member defining a center opening.

2. An explosive device providing upgraded explosive work from low sensitivity bulk explosives confined in a bore hole which comprises in combination a bore hole, a bulk explosive in cylindrical form of substantially the same diameter as said bore hole and light metal substantially saucer-shaped discs, said discs being positioned laterally within said explosive at intervals along the length of said cylindrical explosive, said discs being substantially of the same diameter as said cylindrical explosive, and said cylindrical explosive with said discs being positioned in said bore hole, said discs having a continuous, thick outer rim, said rim having a notch on the top and a notch on the bottom, said notch on the top of said rim of said saucer-sharper disc fitting said notch on the bottom of another of said saucer-shaped discs whereby said discs can be self-stacked, a thin Wall extending inwardly from said continuous outer rim to the rim of a central circular reinforcing member, said thin wall defining a series of openings spaced at equal intervals around said wall, each of said openings extending in length over almost the entire section of the thin wall between said continuous outer rim and the rim of said central circular reinforcing member and being defined in width by the extent of about a twenty degree angle extending outward from the center axis of said central circular reinforcing rnernber and said central circular reinforcing member defining a center opening.

3. The device as defined in claim 2 wherein each of said light metal discs is a die cast magnesium alloy article and the center opening of the circular reinforcing member accommodates a shaped charge.

References Cited in the file of this patent UNITED STATES PATENTS 1,767,182 Lisse June 24, 1930 2,026,454 Benzing Dec. 31, 1935 2,245,751 Biackmore Jan. 17, 1941 2,247,169 Gilbertson June 24, 1941 2,448,648 Carey Sept. 7, 1948 2,586,891 Epler et al. Feb. 26, 1952 2,760,434 Ruth Aug. 28, 1956 2,837,996 Klotz June 10, 1958 2,926,604 MacLeod Mar. 1, 1960 3,016,831 Coursen Ian. 16, 1962 

1. AN EXPLOSIVE DEVICE PROVIDING UPGRADED EXPLOSIVE WORK WHICH COMPRISES IN COMBINATION A CYLINDRICAL EXPLOSIVE HAVING POSITIONED THEREIN AT INTERVALS LATERALLY ALONG THE LENGTH OF SAID EXPLOSIVE ELECTRON CONDUCTING SUBSTANTIALLY SAUCER-SHAPED DISCS AND A CONFINING STRUCTURE FOR SAID EXPLOSIVE AND DISCS, SAID DISCS HAVING A THICK CONTINUOUS OUTER RIM, SAID RIM HAVING A NOTCH ON THE TOP AND A NOTCH ON THE BOTTOM, SAID NOTCH ON THE TOP OF SAID RIM OF SAID SAUCER-SHAPED DISC FITTING SAID NOTCH ON THE BOTTOM OF ANOTHER OF SAID SAUCER-SHAPED DISCS WHEREBY SAID DISCS CAN BE SELF-STACKED, A THIN WALL EXTENDING INWARDLY FROM SAID CONTINUOUS OUTER RIM TO THE RIM OF A CENTRAL CIRCULAR REINFORCING MEMBER, SAID THIN WALL DEFINING A SERIES OF OPENINGS SPACED AT EQUAL INTERVALS AROUND SAID WALL AND EXTENDING IN LENGTH OVER ALMOST THE ENTIRE SECTION OF THE THIN WALL BETWEEN SAID CONTINUOUS OUTER RIM AND THE RIM OF SAID CENTRAL CIRCULAR REINFORCING MEMBER AND SAID CIRCULAR REINFORCING MEMBER DEFINING A CENTER OPENING. 